1. Technical Field
This invention relates generally to the field of lighting fixtures, and more particularly, to an apparatus and method which are particularly useful in the installation of adjustable lighting fixtures.
2. History of Related Art
Lighting fixtures such as spotlights, including wall or ground-mounted lights and ceiling-mounted downlights, are well known in the art for task lighting and artistic illumination of interior and exterior settings. Such lighting fixtures are frequently adjustable and may be categorized according to two different types: a conventional lamp based fixture illuminated by means of electric power connected to the lamp socket within the fixture, or a remote lamp based fixture relying on a fiber optic illuminator to pipe light through an optical light guide to the body of the fixture. In each case, it is generally desirable to easily and precisely adjust the beam pattern provided by the fixture, and then rigidly fix the orientation of the fixture so that the resulting illumination pattern remains constant. Implementing such adjustments are most desirable after the fixture has been mounted in place.
Prior art lighting fixtures generally provide some type of gimballed sphere which can be locked in place by tightening set screws located on the side of the fixture. However, these set screws are often located above the ceiling height where the downlight resides, and therefore cannot be easily adjusted after the fixture is mounted to the ceiling.
Another problem which exists with currently available fixtures is the tension that exists between providing a fixture that accommodates adjustable illumination positioning, while enabling a rigid fixation of the illumination after adjustment. Providing easy adjustment often disables the ability to firmly lock the fixture into its final position. Conversely, the ability to firmly situate the fixture after final adjustments often defeats the ability to easily adjust the fixture, either initially or at some future time. This difficulty is exacerbated in the case of fiber optic fixtures, since the forces within the fiber as it curves away from the fixture tends to move the fixture out of adjustment over time. This is especially true for large diameter glass-core fiber, and large diameter, solid-core plastic fibers, which can be particularly rigid. Some of the currently-available fixtures attempt to solve this problem by the inclusion of a strain relief above the fixture. However, this tends to increase the total fixture height, is more expensive, and precludes the use of such fixtures in low-clearance applications.
Therefore, what is needed is a lighting fixture which allows adjustable placement of illumination after installation. Such a fixture should be easy to adjust, while providing for firm fixation of the illuminating elements after adjustment. Further, such a fixture should be useful for both conventional and fiber optic lighting, while accommodating low-clearance installation heights (e.g., as little as 2 inches above the ceiling). Finally, such a fixture should obviate the need for a separate strain relief when used with optical light guides, and require a minimal number of parts for ease of manufacture and inexpensive production. Any tools required for installation should be readily available, or so inexpensive as to be sold along with the fixture itself.
The present invention is embodied by a post-installation adjustable lighting fixture which includes a typically-spherical eyeball captured between a flange and a retention means. The flange and retention means both have circular openings for swivelable reception and retention of the eyeball, respectively. The eyeball is captured between the flange and retention means by a rotatable coupling means, and an adjusting tool is used after attachment to the eyeball, to position the eyeball with respect to the retention means for the desired illumination effect. The fixture is designed so that attachment of the adjustment tool and positioning of the fixture illumination can occur after the fixture is installed at a fixed location, such as in a ceiling.
The eyeball may include a lens for focusing the light from a conventional lamp, or light provided by the introduction of a fiber optic light guide into the interior of the eyeball. The eyeball may be cushioned against the presence of the retention means and flange by use of upper and/or lower rings made out of a lubricious material, such as an acetyl resin.
The adjustment tool is open-ended, and may be left in place (i.e., attached to the eyeball) after it is used to adjust the fixture illumination. The tool may include internal grooves to control glare from the fixture and/or a filter to modify the illumination pattern provided by the fixture.
The present invention also includes a method of installing a lighting fixture for optical fiber which includes the steps of inserting the fiber into the eyeball, adjusting and fixing the insertion point of the fiber to produce a predetermined illumination pattern, attaching the retention means to the flange so as to capture the eyeball, attaching the adjustment tool to the eyeball and adjusting the position of the eyeball with respect to the retention means, and fixing the position of the eyeball with respect to the retention means by tightly engaging the retention means to the flange. The method may also include the steps of inserting the optical fiber through an opening in the flange and mounting the flange to a ceiling. Also, the upper and lower rings mentioned previously may be inserted between the eyeball, the flange, and the retention means. Finally, a filter may be placed into the adjustment tool before attachment to the eyeball and the adjustment tool may be separated from the eyeball after installation and adjustment is complete.